# Effects of Brazilian Pepper Tree (Schinus terebinthifolius Raddi) Ethanolic Leaf Extract on Growth Performance and Expression of Intestinal Immune-Related Genes in Nile Tilapia (Oreochromis niloticus)

## TL;DR

A Brazilian pepper tree extract improved growth and immunity in Nile tilapia, suggesting it could be a natural feed additive for aquaculture.

## Contribution

The study identifies the extract's bioactive compounds and demonstrates its dose-dependent effects on fish growth and intestinal immunity.

## Key findings

- Higher doses of the extract increased growth rate, weight gain, and feed efficiency in Nile tilapia.
- The extract modulated intestinal immune-related genes, promoting anti-inflammatory and immune protection responses.
- The extract's bioactive compounds suggest potential as a sustainable feed additive in aquaculture.

## Abstract

This study examined a natural leaf extract from the Brazilian pepper tree and its effects on Nile tilapia growth and gut health. Chemical analysis showed the extract contains beneficial compounds such as phenolics, flavonoids, tannins, and triterpenoids. In a 60-day feeding trial, fish given higher doses of the extract grew faster, gained more weight, and used feed more efficiently than controls, with reduced body fat. The extract also influenced immune-related genes, increasing anti-inflammatory signals and immune protection at appropriate doses. Overall, the results suggest this plant extract could be a safe, natural feed additive to improve growth, immunity, and sustainability in tilapia aquaculture.

This study investigated the ethanolic leaf extract of Brazilian pepper tree (Schinus terebinthifolius Raddi) for its metabolite composition and effects on growth performance and intestinal immune gene expression in Nile tilapia (Oreochromis niloticus). Ultra-performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS/MS) in positive and negative modes revealed a diverse profile of 33 peaks in each polarity, identifying key compounds such as phenolic acids (e.g., gallic acid and ferulic acid), flavonoids (e.g., myricetin-O-glucoside and quercetin 3-O-glucoside), gallotannins (e.g., glucogallin and pentagalloylglucose), and triterpenoids (e.g., masticadienoic acid). A 60-day feeding trial with four groups (control and three extract doses; 0.5%; T0.5%, 1%; T1% and 2%; T2%) demonstrated dose-dependent enhancements in growth metrics, where final body weight increased by up to 106.9 ± 3.6 g, weight gain% by 197.3 ± 3.5%, and the growth rate got more than doubled in T2% (2.4 ± 0.1), alongside improved feed conversion ratio (1.24 ± 0.01) at 30 days and condition factor (stabilized at 2.1 ± 0.0) at 60 days post-feeding. Viscero- and gastro-somatic indices declined insignificantly in most feed groups, indicating improved muscle growth. Biphasic patterns were observed in intestinal gene expression as follows: over 60 days, the IL-1β gene upregulated at low doses but returned to normal at high doses. The IL-10 gene upregulated progressively, promoting an anti-inflammatory balance. In fish fed medium and high doses (T1% and T2%), the IgM gene is upregulated, supporting humoral immunity. These outcomes, linked to the extract’s previously described antioxidants, anti-inflammatory, and antimicrobial bioactive compounds, suggest that S. terebinthifolius is a promising natural feed additive for sustainable tilapia aquaculture and warrants further validation for commercial application.